Field
The present disclosure relates to a field emission device, and, in particular, to a field emission device with a multiple-electrodes configuration.
Related Arts
The field emission emitter has been employed in a variety of devices including displays, engineering or medical X-ray tubes, etc. A performance of such devices may depend on characteristics of electron-beams from the emitter, including a beam convergence, current density, or etc.
The diode-configured field emission device with two electrodes has cathode and anode electrodes, where the cathode electrode has an emitter attached thereto to emit electrons. In a field emission, it may require comparatively large field strength due to a large spacing between the cathode and anode electrodes. This may lead to a difficulty to control the emitted electron-beams.
To solve this problem, there has been set forth the triode-configured field emission device having cathode and anode electrodes and one additional electrode, where using the additional electrode, a current amount as emitted, an electron-beams size, electron-beams convergence may be controlled.
The additional electrode is formed in a meshed-structure with apertures to transmit the electrons. Thus, the electrons emitted from the emitter may reach more efficiently the anode electrode. In this time, structural features of the additional electrode such as the apertures size and arrangement, etc. may affect field emission characteristics of the device. For example, the larger aperture size may lead to a larger effective amount of currents reaching from the emitter through the additional electrode to the anode. However, such a large aperture size may lead to a reduced gate field effect applied to the emitter via a distortion of a potential distribution between the additional electrode and cathode electrode. This may result in a reduced initial electron emission and thus a reduced current amount as emitted.
Therefore, there may a need for an electron material to allow effective controls of the electron-beams size and convergence while providing a high electron transmittance therethrough and a high gate field effect.